Method of manufacturing a tube and tin radiator

ABSTRACT

A method of manufacturing a radiator from a strip of sheet material having a maximum thickness of 1 mm; by means of a die, rows of uniform apertures are punched, after which the strip is cut longitudinally through the centers of the apertures, so that strips having a maximum width of 25 mm are formed. The strips are then spaced apart a maximum distance of 3 mm with the apertures in alignment, and cooling water pipes are inserted in each row of apertures and soldered.

United States Patent 1 Hoek [451 Jan. 1,1974

1 1 METHOD OF MANUFACTURING A TUBE AND TIN RADIATOR [75] Inventor: Willem Van Der Hoek, Emmasingel,

Eindhoven, Netherlands [73] Assignee: U. S. Philips Corporation, New

York, NY.

[22] Filed: Apr. 3, 1972 [21] Appl. No.: 240,589

[30] Foreign Application Priority Data Feb. 17, 1972 Netherlands ..72/0207] [52] US. Cl. 29/1573 B, 29/415, 29/416, 113/118 A [51] Int. Cl B2ld 53/02, B23p 15/26 [58] Field of Search 165/151; 29/1573 A, 29/1573 B, 415, 416; 113/118 A [56] References Cited UNITED STATES PATENTS 2,092,170 9/1937 Kritzcr et a1. 29/1573 B 3,407,874 10/1968 Gier 165/151 2,512,540 6/1950 Friedman 165/146 2,913,806 1l/1959 Kritzer 29/157.3 B X FOREIGN PATENTS OR APPLICATIONS 709,555 5/1965 Canada 29/l57.3 B

Primary ExaminerRichard J. Herbst Assistant ExaminerD. C. Reiley, Ill Attorney-Frank R. Trifari [57] ABSTRACT A method of manufacturing a radiator from a strip of sheet material having a maximum thickness of 1 mm; by means of a die, rows of uniform apertures are punched, after which the strip is cut longitudinally through the centers of the apertures, so that strips having a maximum width of 25 mm are formed. The strips are then spaced apart a maximum distance of 3 mm with the apertures in alignment, and cooling water pipes are inserted in each row of apertures and soldered.

5 Claims, 8 Drawing Figures PATENTED JAN 1 74 SHtEI 1 [1f 4 PATENIED 3.781.960

sum 2 or 4 PAIENTED H974 3.781.960

sum 3 [IF 4 METHOD OF MANUFACTURING A TUBE AND TIN RADIATOR The invention relates to a method of manufacturing a radiator which comprises a number of cooling water pipes which communicate at one end with an inlet and at the other end with an outlet for cooling water. The radiator furthermore comprises a number of Strips which extend at right angles to the cooling water pipes and are connected to said pipes in a heat-conducting relationship.

Radiators of the type to which the present invention relates are used for example in the cooling system of combustion engines to give off thermal energy to the atmosphere. In these engines the radiator is usually accommodated under the bonnet of the relevant vehicle.

The available space and in particular the available front surface is restricted. In particular for engines having higher powers and also for external combustion engines, in which two cases a large amount of thermal energy has to be dissipated via the radiator, it is of great importance to have a radiator construction available which has a large cooling capacity per unit of front surface area.

In order to achieve this, a'radiator has already been proposed which consists of a number of elements which enclose an angle with each other so that a zig-zag structure is formed for the front and rear surface. This radiator is furthermore characterized by the fact that the thickness of each element is at most 25 mm and furthermore the hydraulic diameter of the air ducts in the elements is smaller than 2 mm. In this manner a radiator is obtained having an extremely large cooling capacity per unit of front surface area.

It is the object of the present invention to provide a method with which the above-described radiator can be series-produced in a simple and hence cheap manner. The method according to the invention is characterized in that a strip of sheet material having a thickness of at most 1 mm is provided, by means of a die, with a number of rows of uniform recesses. Afterward the strip is cut in its longitudinal direction by means of a cutting tool across the centre of the said recesses, so that a number of strips is obtained having a width of at most 25 mm, the said recesses opening into a side edge of said strips. Next the strips at mutually equal distances of at most 3 mm are directed on their sides in parallel, with the recesses in alignment, and are conveyed along a pipe inserting mechanism in which a cooling water pipe is inserted into each row of recesses. The formed assembly of strips and pipes is then soldered together and the strips are subsequently interrupted at a given length to obtain a radiator element. It is possible in this comparatively simple manner to series-produce radiator elements having a particularly large cooling capacity. This has become possible in particular in that the strips have a width of less than 25 mm, so that in the direction of the width one row of cooling water pipes will do which can easily be inserted since the recesses open into the sides of the strips. The transport of the strips past the pipe inserting mechanism can be carried out by moving the pipes present already in the recesses so that a good positioning of the recesses relative to each other in the juxtaposed strips is always ensured.

In certain circumstances it may occur that the strips between the cooling water pipes are slightly inaccurate as regards size, which leads to bending of the strips and contact between the strips as a result of which the optimum radiator structure threatens to be lost. In order to prevent this, the starting material in a further embodiment is sheet material having a thickness of at most 4 mm, which sheet is passed between two rollers one of which comprises a number of parallel recesses extending according to a generatrix and having a depth of at least 3 mm and the other of which is smooth so that a strip of sheet material is obtained which is flat on one side and comprises ribs of the other side.

The soldering together of strips and pipes may of course be carried out in various manners. According to a favourable embodiment of the method aaccording to the invention, starting material is sheet material comprising a layer of joining material and/or the strips, after punching the recesses, are provided with such a layer, while the pipes are also covered with a layer of joining material, the joining being carried out by passing a warm current of gas through the assembly of pipes and strips. As a result of the large cooling capacity of the assembly of strips and pipes, a very rapid heating will occur so that a high operating speed and short joining zone can be maintained.

According to a further favorable embodiment the insertion of the cooling water pipes is carried out by making the pipes to length and then flattening said pipes, at least over the length covered by the strips, to a thickness which corresponds substantially to the width of the recesses in the strips. Next these pipes are supplied to one or two drivable pipe drums in which the pipes are retained to in the proximity of the position where the juxtaposed strips substantially contact the pipe drum and the pipes engage in the relevant recesses and the drums take along the strips via the pipes. In this manner a good synchronization of the movement of the drums and of the strips is automatically ensured.

In order that the insertion of the pipes in the recesses can occur smoothly, in a further embodiment the strips are supported, at least at the area where they substantially contact the pipe drum, on their side remote from the relevant drum by a slightly curved surface so that the recesses facing said drum are also slightly bent open. This also has the great advantage that, after the insertion into the recesses, the pipes are clamped which benefits the heat transfer.

In a further favorable embodiment, the recesses are provided in the strips in such manner that they enclose a small angle of at most 20 with the normal on the side of the relevant strips.

Another embodiment of the method according to the invention is characterized in that, during punching the recesses, recesses of a different shape are punched at regular distances which, after soldering, form fracture lines in the formed assembly along which the radiator elements can be separated, after which 'a number of said elements are arranged at an angle with each other and are joined together.

The invention furthermore relates to a radiator obtained according to the above-described method. This radiator combines a surprisingly large cooling capacity with comparatively low costs of manufacture and material. The invention will be described in greater detail with reference to the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1, la, 1b, and 16 show in fragmentary views in perspective, initial stages of manufacture according to this invention.

FIGS. 2 and 3 show in fragmentary views in perspective subsequent stages in said manufacture.

FIG. 4 shows a front elevation view of a radiator formed by this invention.

FIG. shows a top plan view of the radiator of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 to 5 show diagrammatically by way of example the manufacture of a radiator. Reference numeral 1 in FIG. 1 denotes a strip of sheet material having a thickness of 0.l mm. This strip is guided through a punching device 2 which is shown diagrammatically and comprises a block of dies containing a large number of dies which punch rows of recesses 3 in the sheet, and one row of dies which punch recesses 4 of a different shape.

The strip of material is then guided through a cutting machine 5 having a number of knives 6 which cut the sheet into a number of strips 7 having a width of 16 mm. The knives 6 cut exactly across the centre of the recesses 3 and 4 so that said recesses open into a side edge of each of the strips 7. The recesses 3 extend slightly obliquely relative to the relevant side wall of the strip. This is not necessary; in certain circumstances the recesses 3 may have a shape as is shown in FIG. la in which they extend at right angles to the line along which the knives 6 cut the sheet. An advantage of this latter is the much simpler form of the dies. The formed strips 7 are wound on a reel 8 and that in such manner that the recesses 3 of all the strips face the same side with their open sides, which means that every other strip has to be turned. After a certain length of strip has been wound on the reel 8, the strip is broken or cut or clipped and the full reel is ready for further processing.

A number of full reels 8 are placed on uncoilers 9 (FIG. 2) in such manner that in each reel the recesses 3 are directed upwards with their open sides. The strips 7 are then guided from the reels through one or more orienting mechanisms 10 which are a type of comb-like guides having teeth which are approximately 0.3 mm thick and placed approximately 0.1 mm apart. The strips 7 are guided between the teeth.

It appears from the above that one strip and one intermediate distance together cover a width of 0.4 mm. So for a radiator having a height of 40 cm, already 1,000 strips are necessary. So for practical dimensions of radiators, more reels will be necessary than the 6 which are shown in the drawing. Considering some 40 strips each 16 mm wide per reel, even then reels are necessary in that case. This means that the utmost care should be paid to the orientation and support of the running strips and therefore a plurality of orienting mechanisms 10 will be used in practice.

After the last orienting mechanism 10, the strips 7 are transferred to a conveyor belt 11 (FIG. 3) the surface of which is provided with a large number of moustache hairs having a thickness of approximately 0.3 mm and a transverse distance of 0.1 mm so that they take over the function of the orienting mechanism 10 and accurately hold the strips apart.

Over this conveyor belt 11 which serves as a support and an orienting mechanism and the guide rollers 11' of which are placed so that the conveyor belt below the drum 12 runs slightly convex, the strips 7 are passed below a pipe drum 12 which comprises a shaft 13' which is coupled to a driving mechanism not shown. Circular pipes 14 cut to length are supplied via a channel 15 between two rollers 16 rotating in opposite directions. The pipes 14 are slightly wider than the rollers 16. Between the rollers 16 the pipes 14 are flattened to be oval, the ends projecting from the rollers remaining circular so that afterwards they can easily be soldered in circular holes of the lower and upper cooling water collecting ducts, respectively, of the radiator.

Via duct 17 the flattened pipes 14 run to the pipe drum 12 which comprises on its circumference recesses 18 into which, each time when they pass below the duct 17, a pipe is fed. The pipes laid in the recesses 18 are maintained there by the shield 20 which surrounds a part of the drum with a small amount of play. The shield 20 terminates just above the strips 7 so that when the pipes 14 have arrived there, they slide out of the recesses 18 in the drum into the recesses 3 of the strips 7. As a result of the slightly convex shape of the conveyor belt 11, the strips 7 will also bend slightly, as a result of which the recesses are bent open a bit so that the pipes 14 can easily be inserted. The strips 7 are further moved with the drum 12 because said drum comprises at either end catches 13 which engage the pipes present in the recesses as a toothed wheel so that a good synchronization of the movements of drum and strips is automatically ensured. Upon moving, the relevant pipe gradually leaves the recess 18 and fully engages in the relevant recess 3 in which, as a result of the recoil of the strips the pipes 7 are clamped in the recesses 3 so that a good thermal contact is ensured. This means that the strips 7 are now fixed relative to each other so that no guides are necessary any more. In this manner, all the recesses 3 are provided with a pipe, after which the assembly of strips and pipes, which had all been tin-plated before the operation started, are guided through a heating device 21. In this device 21, a flow of warm gas is passed along the strips and pipes. Heating of the strips and pipes occurs very rapidly as a result of the fine subdivision and consequently high heat transfer, so that the soldering together of strips and pipes occurs in a very short time. This means that also in the case ofa high speed of the strips, the dimension of the heating device may be small. It is to be noted that instead of tin solder, other joining materials, including glue, may be used. After the heating device, an assembly of pipes and strips is obtained which can be clipped or broken at given lengths at the areas where the special punches 4 have been provided. The resulting elements may then be arranged in a zig-zag form. Such a radiator folded in zig-zag form is shown diagrammatically and partly in FIGS. 4 and 5.

It has been found that, when in such a radiator the width of the strips is not chosen to be larger than 25 mm, while in combination therewith with a minimum hydraulic diameter of the ducts through which the air flows, the ratio b/dh is smaller than 15 (b width of the strips and d,, hydraulic diameter), a radiator is obtained having a cooling capacity which is considerably larger than that of the known radiators.

As appears from the manufacturing method described above, the radiator in question furthermore has the advantage of light-weight and the construction is readily suitable for mechanisation.

It may occur in certain circumstances that the strip parts present between the pipes have become slightly convex due to inaccuracy of measure and contact each other. In order to prevent this it is possible, as is shown in FIG. lb, to start from sheet material having a thickness of 0.4 mm and to pass this between two rollers 23 and 24 of which roller 23 is constructed fiat and roller 24 comprises recesses 25 having a depth of 0.3 mm. In this manner a sheet of 0.1 mm thickness is obtained having ribs 26 of approximately 0.3 mm high. In the punching device 2, said sheet is then provided with the rows of recesses 3 and 4, respectively. The recesses 25 need not be continuous but may be interrupted at regular distances. In this case the result is that the ribs 26 also show regular interruptions. Instead of ribs they are rows of cams.

The further operation is the same as already described, on the understanding that the orienting mechanisms should now be constructed differently, namely as a channel in which all the strips engage each other. In the heating device 21, not only the pipes are soldered to the strips, but the ribs 26 are also soldered to the flat side of the adjacent strips. In this manner an extremely rigid construction is obtained for a radiator which is nevertheless very finely divided.

Although the recesses 3 in the embodiments of FIGS. 1 and 1a are punched so that after cutting, said recesses in each strip open only in one side, it is also possible to provide the recesses as is shown in FIG. 10. The result of this is that the recesses in each strip now alternately open into both sides. For one set of recesses, the pipes must be inserted from above as shown in FIG. 3, whereas for the other set of recesses a second pipe inserting mechanism is necessary which introduces the pipes from the other side.

What is claimed is:

l. A method of manufacturing a radiator which comprises a plurality of cooling water pipes having inlets and outlets and are positioned generally parallel to a first axis, and a plurality of strips of sheet material of maximum thickness 1 mm extending between said pipes and generally at a right angle to said axis, and

connected in heat-transfer relationship to said pipes, comprising the steps: forming a plurality of rows of uniform apertures in a single sheet of material having a maximum thickness of l.mm, cutting the sheet into longitudinal strips having maximum width of 25 mm, the cuts being through the centers of said apertures, each strip forming a plane defined by said width, thickness, and length, aligning the strips with their planes generally parallel and spaced apart a maximum of 3 mm, and also aligning said apertures in the strips to form rows of recesses generally normal to the planes of said strips, inserting a cooling water pipe in each of said rows of apertures, and soldering said pipes and strips where each strip intersects a pipe, thus forming a radiator element.

2. A method according to claim 1 wherein said sheet material has initial thickness in the range of 1-4 mm, comprising the further steps compressing said sheet between rollers one of which has a smooth cylindrical surface and the other of which has grooves in its cylindrical surface parallel to the roller axis, said grooves having depth of at least 3 mm, whereby said rollers compress the sheet to a thickness of 1 mm, with ribs formed on one side of the sheet corresponding to said grooves.

3. A method according to claim 1 comprising the further steps of forming on said strips and pipes a layer of solder before the pipes are inserted into said apertures; heating a gas to temperature above the melting point of said solder, and permanently joining said pipes and strips by flowing said heated gas into contact with said solder layers, where the pipes and strips intersect.

4. A method according to claim 1 comprising the further steps of partially flattening said pipes along their lengths between their ends from circular to oral crosssection.

5. A method according to claim 1 comprising the further steps of forming fracture perforations at specified locations intermediate said apertures, and fracturing a subsequently manufactured radiator element into separate parts along a line defined by a plurality of said perforations. 

1. A method of manufacturing a radiator which comprises a plurality of cooling water pipes having inlets and outlets and are positioned generally parallel to a first axis, and a plurality of strips of sheet material of maximum thickness 1 mm extending between said pipes and generally at a right angle to said axis, and connected in heat-transfer relationship to said pipes, comprising the steps: forming a plurality of rows of uniform apertures in a single sheet of material having a maximum thickness of 1.mm, cutting the sheet into longitudinal strips having maximum width of 25 mm, the cuts being through the centers of said apertures, each strip forming a plane defined by said width, thickness, and length, aligning the strips with their planes generally parallel and spaced apart a maximum of 3 mm, and also aligning said apertures in the strips to form rows of recesses generally normal to the planes of said strips, inserting a cooling water pipe in each of said rows of apertures, and soldering said pipes and strips where each strip intersects a pipe, thus forming a radiator element.
 2. A method according to claim 1 wherein said sheet material has initial thickness in the range of 1-4 mm, comprising the further steps compressing said sheet between rollers one of which has a smooth cylindrical surface and the other of which has grooves in its cylindrical surface parallel to the roller axis, said grooves having depth of at least 3 mm, whereby said rollers compress the sheet to a thickness of 1 mm, with ribs formed on one side of the sheet corresponding to said grooves.
 3. A method according to claim 1 comprising the further steps of forming on said strips and pipes a layer of solder before the pipes are inserted into said apertures; heating a gas to temperature above the melting point of said solder, and permanently joining said pipes and strips by flowing said heated gas into contact with said solder layers, where the pipes and strips intersect.
 4. A method according to claim 1 comprising the further steps of partially flattening said pipes along their lengths between their ends from circular to oral cross-section.
 5. A method according to claim 1 comprising the further steps of forming fracture perforations at specified locations intermediate said apertures, and fracturing a subsequently manufactured radiator element into separate parts along a line defined by a plurality of said perforations. 